The provincial health department in Durban has said that AIDS patients in the province are under siege from drug addicts who rob them of their antiretroviral treatment to get high.
The life prolonging drug Stocrin, one of the antiretroviral drugs used to fight AIDS, is reportedly crushed and mixed with marijuana and sold in the townships around the coastal city.
The health department has warned that the trend could spark shortages in the city's hospitals and health centres, in one of the provinces worst afflicted by the AIDS pandemic.
"This practice is disturbing, a large number of HIV patients depend on the state sponsored treatment to stay healthy," spokesman Leon Mbangwa told AFP.
The department dismissed media reports that health workers at certain hospitals were involved in selling HIV drugs to criminal rings, who then target patients when nurses cannot keep up with the demand.
"All medication is kept in the hospital pharmacy and only certain levels of nurses have access to it," said Mbangwa.
Patients collecting medication at the Prince Mshiyeni Memorial Hospital in Umlazi, south of Durban have complained of being ambushed by criminals on their way home.
Others have had their home ransacked by thugs looking for the lifesaving drugs.
"The concoction of Stocrin and dagga (marijuana) is very dangerous and eventually leads to death. The drug mixture breaks down the immune system and reduces the resistance of the body," said Anwar Jeewa, director of the Minds Alive rehabilitation centre.
South Africa has the highest number of HIV sufferers in the world with around 5.5 million of the 47 million population affected by the virus, and the world's biggest ARV programme with more than 478,000 people registered for treatment.